The present invention relates to a system for flexibly adapting a service panel of conventional type for connection with a power cord, which cord can be one of several standard types, each type having a characteristic prong arrangement on its plug-in head portion. The present invention relates, in particular, to a system utilizing an electrical receptacle that is suitably configured for quick plug-in mounting on the service panel and that provides upper contacts suitably arranged for direct engagement by the prongs of the power cord.
In electrical wiring systems generally, a service panel provides a centralized site for redistributing power to secondary supply lines. One or more devices, such as circuit breakers, are normally mounted in predetermined locations on the panel both to provide automatic surge protection relative to the secondary lines and to allow manual cutoff of power to these lines for safety reasons during servicing of the system.
In modern panels of conventional design, a power distribution board is normally provided from the surface of which a linear array of conductive blades upwardly stand so that each blade is in parallel relationship to the others. These blades serve as the power terminals for the board. The board is normally mounted in centered position on a wider mounting bracket, which bracket provides, on either side of each blade, at least one hook-like retaining tab. This tab is designed to received a lip member of the type normally provided on the rearward end of a standard circuit breaker module so as to permit the rearward end of such module to be pivoted about the tab in order to rotate a female-type terminal on the forward end of the module into engagement with the corresponding blade. This type of installation procedure is described in further detail in Hammerly U.S. Pat. No. 2,910,630 and in Edmunds U.S. Pat. No. 3,120,628, and a similar procedure used for installing a surge-protector module is described in Schacht U.S. Pat. No. 4,642,733.
As described in Klein U.S. Pat. No. 3,463,967 and in Myers U.S. Pat. No. 4,157,582, circuit breaker modules are available in both full- and half-width sizes, so that each blade can be engaged by as many as four circuit breaker modules at one time with one module abutting each quadrant of the blade. In place of blade-like power terminals, it is also conventional to use socket-like power terminals, in which case male-type contacts are provided on the circuit breaker module, as shown in Harper U.S. Pat. No. 4,117,285.
Between the line terminal on its forward end and a corresponding load terminal on its rearward end, each circuit breaker module provides an automatic trip mechanism so that any secondary supply line connected to the load terminal is protected against electrical surges. A manual throw switch is also normally provided on each module to reset the automatic trip mechanism and to allow manual cutoff of power to the corresponding secondary supply line.
In some instances, the secondary supply lines terminate at electrical outlets which, because of their location, type or number, are unable to provide an adequate interface for every power cord requiring connection to the system, particularly when the number of users of the system tends to fluctuate, such as at mobile home parks, trailer parks, boat docks and marinas. To sufficiently serve the needs of all users at such facilities, one approach has been to construct temporary hookups by running additional lines from the primary service panel to auxiliary electrical panels or boxes that have been specifically equipped with power outlets or receptacles of a kind compatible with the type of power cords requiring hookup. Two different types of auxiliary service panels are shown in "I-T-E.RTM. and Other Siemens Electrical Products/Speed Fax 1987-88," a product catalog published by Siemens AG based in Munich, Germany, p.114, and in "Digest 166, Electrical and Advanced Technology Products" a product catalog published by Square D Company of Palatine, Ill., p.24 (March 1987). The difficulty of this approach, however, is that technically skilled and highly-paid personnel need to be on hand to construct these types of system additions, particularly if the resulting connections and load ratings are to properly comply with electrical code requirements. Furthermore, there may be no suitable installation sites available at locations removed from the primary service panel for mounting additional electrical panels or boxes.
A second approach that has been proposed is to use a specially constructed panel in which only certain mounting locations on the panel are designed to receive standard-size circuit breaker modules, with the remaining mounting locations being modified so that each can mount a corresponding plug-in receptacle module of nonstandard design. Each receptacle module, in turn, can be directly engaged by one of the power cords requiring connection. This approach is described, for example, in Buxton U.S. Pat. No. 3,743,891 with further modifications being described in Buxton et al., U.S. Pat. No. 3,922,586. As described in these references, the plug-in receptacle module includes a circuit breaker section that is quite similar in overall size and function to a side-to-side pair of full-size standard circuit breaker modules. This circuit breaker section is coupled in end-to-end arrangement with an electrical receptacle section so as to enable both sections to be contained within a single housing. In accordance with this construction, the plug-in receptacle module has a total length somewhat exceeding twice that of a standard circuit breaker module.
There are, however, several difficulties with the approach just described. As a preliminary matter, a large investment of time and effort is needed to convert existing systems to this approach. For example, each line that is already connected to the existing panel, if it is to be maintained, needs to be disconnected and then reconnected to the specially constructed panel, which process can involve reconnection of a number of different power and ground cables. Moreover, after the specially constructed panel is in place, the capacity of the underlying system to support the type of connections that are actually needed, can, in fact, be diminished, since only a percentage of the mounting locations provided by the specially constructed panel are available for connections involving standard circuit breaker modules whether or not the remaining mounting locations are being used for connections involving plug-in receptacle modules. Furthermore, in order to provide sufficient clearance within the specially constructed panel to accommodate the oversized plug-in receptacle modules, the overall physical arrangement of the various major components of this panel is significantly altered from that of a standard panel. The resulting arrangement is such that even if every mounting location of the panel was able to mount a standard circuit breaker module, there would still be a problem of underutilization of panel space. In contrast with a conventional panel, for example, it is not possible to mount standard circuit breaker modules on the specially constructed panel in a spatially efficient two-ranked array so as to make efficient use of both sides of the linear sequence of power-supplying blades.
Accordingly, an object of the present invention is to provide an improved system for adapting a service panel for temporary connection to one or more power cords.
A related object of the present invention is to provide a system of the above general type which can be readily utilized in conjunction with service panels of conventional type.
Another related object of the present invention is to provide a system of the above general type in which laborious substitution of the existing service panel with an entirely new panel is not required.
Yet another related object of the present invention is to provide a system of the above general type in which the service panel can be fully utilized whether the type of connections needed are entirely of the type requiring a circuit breaker module or entirely of the type requiring an electrical outlet.
Still another related object of the present invention is to provide a system of the above general type which permits efficient utilization of the space within the service panel.